//ECMAScript 2016
//Array.prototype.includes
const arr = ["foo", 1, NaN, false];
//indexOf 返回元素的索引
console.log(arr.indexOf(NaN)); //-1 无法查找数组中的NaN
console.log(arr.indexOf(false)); //3

//includes 返回布尔值
console.log(arr.includes(NaN)); //true

//指数运算符 计算2的10次方
console.log(Math.pow(2, 10)); //1024
console.log(2 ** 10); //1024
